1. Field of the Invention
The present invention is related to a product seizing element in a folder apparatus, having at least one folding cylinder the surface of which forwards products along a respective product travel pass.
2. Background of the Invention
U.S. Pat. No. 5,484,379 discloses a folder assembly for printing presses. A folder assigned to a web-fed rotary printing press includes a pair of cooperating collecting and cutting cylinders to sever a web of paper into web segments. A belt conveyor system enwraps a portion of the surface of the collecting cylinder just before an intake point of paper ribbon between the collecting cylinder and the cutting cylinder. This belt conveyor system prevents the newly created leading edge of the paper ribbon from springing back.
According to the solution of U.S. Pat. No. 5,484,379 a belt conveyor system is arranged adjacent to said collecting cylinder. Said belt conveyor system contacts a leading edge portion of the web of material disposed on the preferred surface of said collecting cylinder. Said belt conveyor system imparts on said leading edge of the web of material in a direction of paper web travel. Thus, said collecting cylinder and said belt conveyor system impart a prestress in said direction of paper web travel of said leading edge with respect to the cylinders surface. By prestressing of said leading edge of said web of material with respect to the cylinders surface the leading edge is forced to slip on the respective cylinders surface. Depending upon the paper stock, the number of ribbons included in the respective web of material, the accuracy of folds to be performed in the later stages depends upon the position in which said newly created lead edge of the web of material is seized by respective seizing elements.
In view of the technical problems encountered in the solution according to the prior art, it is an object of the present invention, to provide for a secure seizing of the new leading edge of the web of material from which respective products are severed without interference of the seizing elements with the cutting operation.
A further additional or alternate object of the present invention is to provide for a motion of seizing elements of said lead edge of the web of material by reliable elements.
A still further additional or alternate object of the present invention is to allow for positive control of the respective products severed from the incoming web of material.
According to an examplary embodiment of the present invention, a paper conducting cylinder of a folder assembly includes:
A cylinder surface having counterparts for cooperation with cutting elements of a cutting cylinder,
product seizing elements assigned to said counterparts on said cylinder""s surface,
said product seizing elements performing an extending movement about a first pivot axis and
said product seizing elements performing a seizing movement about a further pivot axis.
The advantages of the solution according to the present invention are given by the fact that said leading edge portion of the web of material is not subject to a relative movement with respect to the paper conducting cylinder surface. Thus, no misregistration within a leading edge of a web of material comprising a plurality of ribbons occurs. Still further, a motion is imposed on a respective seizing element in a two-step-manner, to allow for an extending movement after the cutting action has resulted in a cut in a first step and then to allow for a seizing motion of a head portion of a seizing element from an upward opened, extended position into a downward directed seizing motion in a second step.
In further advantageous embodiments of the present invention said seizing elements comprise a first and second portion, respectively. Said second portion has an inclined hook-shaped portion to seize a respective leading edge of a web of material. Said leading edge may have a number of layers or ribbons, respectively, to be reliably secured by said seizing element without imposing a relative movement on to said leading edge of the web of material when arranged upon the paper conducting cylinder""s surface. Said product seizing elements are arranged on the circumference of said paper conducting cylinder, assigned to each of respective cutting counterparts on said cylinder surface for the respective cutting operations. For an actuation of said product seizing element on the cylinder surface a plurality of actuating elements are provided to impose a two-step-motion on said respective seizing elements.
Said actuating elements comprise a cam element which may be shaped as a double track cam, having a respective first track and a respective second track. Said tracks include first and second profiles each having low and high dwell-sections, respectively. Said profiles of the respective tracks are the respective cam surfaces cooperating with respective actuating elements such as cam followers of said seizing elements.
Said actuating elements include a fixed pivot axis to which said product seizing element is fastened. Between said fixed pivot axis and said product seizing element a linking element such as a lever or like is mounted. A further actuating element, cooperating with one of said tracks of said double track cam rotates via a link member about a respective secondary pivot axis. Thus, when said second actuating element will rotate via a link member said rotating movement about its secondary pivot axis to extend said seizing element into an extended position about the respective cylinder surface.
Said secondary pivot axis corresponds to a first cam follower cooperating with said previously mentioned first cam profile. In following said first cam profile said first cam follower will be lifted into an extended position moving said product seizing element into an extended position beyond said respective portion of the paper-conducting cylinder surface. Followed by a second actuating element following the respective cam on the respective second track said seizing element being in an extended position will be rotated from its upward position about a secondary pivot axis into a downwardly directed motion a seizing motion thus seizing the respective leading edge of a web of material without imposing a relative movement on to said leading edge of said web of material.
A paper conducting cylinder having a dual-operated-seizing element according to the above mentioned description is advantageously used in a folder apparatus for commercial and newspaper applications.
According to a method of operating a product seizing element a respective product seizing element assigned to the paper conducting cylinders surface extends from a retracted position into an extended position beyond said cylinders surface in a first actuating step and in a second actuating step said product seizing element is moved from an extended position in a downwardly directed movement towards said leading edge position on said paper conducting cylinder surface. Said extending movement step and the seizing movement step performed in a substantially downwardly directed manner will follow each other subsequently for a seizing action without interference with the cutting operation. Said first step describing an extending movement of said product seizing element first portion will move said product seizing element""s first portion into an upward position. Upon actuation of said second actuating element such as a cam follower said product seizing element being in an extended position is moved in a substantially downwardly directed manner to seize the respective multi-layered ribbon of the respective web of material on the surface of the paper conducting cylinder. The respective downwardly directed movement of said product seizing elements first portion towards the paper conducting cylinders surface eliminates any relative movement of said leading edge since said cut leading edge is seized substantially in its registered position in the vicinity of said groove within which said cutting counterparts such as anvil bars are received on the respective paper-conducting cylinder surface.